1. Submission doc.: IEEE 11-14/1426r1 November 2014 Gustav Wikström et al., EricssonSlide 1 DSC and legacy coexistence Date: 2014-11-03 Authors:

2. Submission doc.: IEEE 11-14/1426r1 November 2014 Gustav Wikström et al., EricssonSlide 2 Abstract For scenario S2 (Enterprise) we have studied the situation of legacy STAs coexisting with 802.11ax STAs that use increased CCA Threshold We found no significant impact on the legacy STAs

3. Submission doc.: IEEE 11-14/1426r1 Background [2] indicates negative impact on legacy STAs from DSC STAs Full buffer traffic model used in Uplink in [2] STAs either in back-off or transmitting state Legacy STAs seldom discover idle wireless medium (WM) WM less occupied with file transfer traffic model DSC STA do not monopolize WM usage Mix of Uplink and Downlink file transfers used in this study Intended to closer resemble realistic traffic Slide 3Gustav Wikström et al., Ericsson November 2014

4. Submission doc.: IEEE 11-14/1426r1 Simulation setup Scenario 2 (Enterprise) from [1] 50% Uplink & 50% Downlink traffic Equal buffer (file transfer with varied intensity), file size 1 MB [3] Served traffic per AP (x-axis in plots) is sum of Uplink & Downlink traffic CWmin = 15, CWmax = 1023 STAs are 50% Legacy with CCAT = -82 dBm 50% 802.11ax with CCAT = -62 dBm All APs implement 802.11ax All Downlink transmissions use CCAT = -62 dBm, regardless if receiver is legacy or 802.11ax Preamble detection threshold = CCAT Energy detection threshold = max(CCAT,-62) dBm Slide 4Gustav Wikström et al., Ericsson November 2014

5. Submission doc.: IEEE 11-14/1426r1 Performance Legacy STAs plotted with dashed red curve, 802.11ax STAs with solid red curve In uplink, both legacy and 802.11ax STAs improve on average and in 5 th percentile user throughput In downlink, there is also improvement in 5 th percentile and average throughput, 802.11ax have larger average user throughput gain Slide 5Gustav Wikström et al., Ericsson November 2014 DownlinkUplink

6. Submission doc.: IEEE 11-14/1426r1 Coexistence Scenario 2 - Downlink CCAT -62dBm users do get reduced SINR, but for 90% of the users the delay per packet is also reduced Legacy user’s SINR is less impacted, but they also see a reduction in packet delay Slide 6Gustav Wikström et al., Ericsson November 2014

7. Submission doc.: IEEE 11-14/1426r1 Summary Increasing the CCA threshold from -82 to -62 provides about 20-25% gain in average and 5 th percentile user throughputs Improved performance is also observed for the legacy STAs in a file transfer scenario Slide 7Gustav Wikström et al., Ericsson November 2014

8. Submission doc.: IEEE 11-14/1426r1 November 2014 Gustav Wikström et al., EricssonSlide 8 References [1] IEEE 802.11-14/0980r04 – Simulation Scenarios [2] IEEE 802.11-14/0854r0 – DSC and legacy coexistence [3] IEEE 802.11-14/0866r1 - Traffic modeling and system capacity performance measure